Let me be honest with you.
The b16a, b16b and b18c series engines all have their advantages/ disadvantages in each and own seperate way.
I'm in the process of building probably one of the most expensive n-asp b16a builds in the country. However its amazing how $$ soon adds up and bends you over and you are left with an empty wallet.
If i were to " start over " i would of gone turbo or nos or bigger displacement.
b16a :
At the end of the day you have a b16a. Nos it. blow it up. Laugh. Buy another b16a for peanuts. They go for about 200quid.
If i blow my build i lose BIG £$£$. The rods on their own work out about £600 + 10 week wait ( they are crower rods, but custom one off jobbies to fit a pr3 piston , and smaller bearings as found in the b16b / b18's ) portflow head etc etc.
b16b :
VERY nice engine, however why not just get the b18 itr motor.
b18c :
again very nice, can be built to some serious numbers if you select the right package of parts. Even stock , they are a potential motor with a hella more torque than the b16a/b.
All in all....
If you have a b16a , stick with it. Just bang some nitrous oxide on it !